1. Field of Invention
This invention relates to the fabrication of fiber reinforced plastic parts and more particularly to a method of fabricating such parts so that the outer periphery of the part and all apertures therein are smoothly trimmed.
2. Description of the Prior Art
Fiber reinforced plastic parts have been formed using molding processes in the past and the outer periphery of the part and apertures in the part have been cut following the curing process. The result was a very ragged, fuzzy edge at the finished part and aperture peripheries. In view of the nature of fiber reinforced plastic, these trimming cuts had to be made with diamond cutters, band saws and high speed routers and these instruments had to be replaced frequently due to the difficulty in trimming organic reinforcing material, such as DuPont's Kevlar R. Further, the finished part had to be wet sanded or otherwise treated extensively to remove the rough, fuzzing condition created by this initial trimming. This prior art trimming procedure was not only expensive to accomplish because of the rate at which the expensive cutting tools involved had to be replaced, but also because of the man hours which had to be expended in cleaning up the irregular cuts made during the initial trimming process.
It has also been practice to perform the trimming process while the fiber reinforced plastic is in its uncured state and then place selectively shaped plugs or dams in the aperture so cut out of the uncured reinforced plastic for part curing. This method, however, proved unsatisfactory because it is expensive to fabricate the selectively shaped plugs required, special fixtures are required to hold these plugs in position on the mold during the curing process, and experience has shown that the curing process produced a resin rich area at the aperture surface which is brittle and is prone to crack or break off in handling or during operation.